Banca de DEFESA: LANNA EMILLI BARBOSA LUCCHETTI

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : LANNA EMILLI BARBOSA LUCCHETTI
DATA : 26/06/2023
HORA: 16:00
LOCAL: https://meet.google.com/esz-muic-atx
TÍTULO:

DENSITY FUNCTIONAL THEORY APPLIED TO ELECTROCHEMICAL PROCESSES USING THE COMPUTATIONAL HYDROGEN ELECTRODE

PÁGINAS: 62
RESUMO:

The rising contamination of the environment by organic pollutants, some of which show endocrine disruption activity and are associated with several health issues, motivates an urgent need for novel water treatment methods. The removal of these compounds from sewage and water remains a challenge, since they come from various sources and have different chemical structures. Electrochemical advanced oxidative processes show remarkable potential for this application, where hydrogen peroxide is generated through the 2-electron pathway of the oxygen reduction reaction. This is a strong oxidizing agent, and it can break many organic pollutants and endocrine disruptors in a non-selective way. This study aimed to investigate the oxygen reduction reaction and the hydrogen peroxide generation in carbon-based materials functionalized with metallic oxides using density functional theory (DFT) and computational methods. A literature review from the last four years has been carried out to identify the current trends in theoretical catalysis and the methodologies employed to investigate these systems. We observed a significant trend among theoretical papers to utilize graphene functionalized with different atoms/defects as the proposed model for electrode catalysts’ surfaces for this application. Besides, we noted that the computational hydrogen electrode model has proven to be the main approach to accessing the thermodynamics of these electrochemical processes while also reducing computational costs. Then, based on the previous experiments from our research group, cerium oxide was chosen as the starting material. In addition, based on our literature review, the computational hydrogen electrode model was employed to investigate the catalytic activity of different ceria surfaces. The results indicated that among all stoichiometric surfaces considered in this study, the (100) had the best catalytic activity for hydrogen peroxide electrogeneration. Thereafter, the role of oxygen vacancies was investigated, and it was noted that low index surfaces (110) and (111) — that would be totally inactive otherwise — have a good activity when the oxygen vacancies are created. Hence, oxygen vacancies are of paramount importance for the catalytic activity of ceria surfaces. Finally, the hydrogen peroxide electrogeneration with the water oxidation reaction was theoretically proposed. This is an alternative reaction route to the oxygen reduction. The results indicated that the (110) stoichiometric surface, initially inactive towards the oxygen reduction, is a great candidate for the hydrogen peroxide generation with this route. This part of our work can inspire and motivate future experimental researchers. Briefly, over the course of this research project, previous experimental results have been corroborated with atomistic computational simulations, and novel data was obtained regarding the catalytic activity of ceria surfaces with DFT calculations, finally shedding a light on experimental observations. This research also generated theoretical data that might be employed for the synthesis and optimization of novel materials.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1544381 - MAURO COELHO DOS SANTOS
Membro Titular - Examinador(a) Externo ao Programa - 1760410 - JEVERSON TEODORO ARANTES JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - PATRICIA ALVES CARNEIRO - UFF
Membro Titular - Examinador(a) Externo à Instituição - SAMIRA SIAHROSTAMI - UOFC
Membro Titular - Examinador(a) Externo à Instituição - LEANDRO SEIXAS ROCHA - UPM
Membro Suplente - Examinador(a) Interno ao Programa - 1544403 - MAURICIO DOMINGUES COUTINHO NETO
Membro Suplente - Examinador(a) Externo ao Programa - 2604737 - EVERALDO CARLOS VENANCIO
Membro Suplente - Examinador(a) Externo à Instituição - ALBERICO BORGES FERREIRA DA SILVA - USP